The present invention generally relates to a cylinder head for an internal combustion engine, and more particularly relates to a cylinder head including rib formations.
A typical cylinder head for an internal combustion engine is formed by a casting process and has an inner wall, an outer wall, and sidewalls. The cylinder head may have three regions, typically referred to as the upper deck, the middle deck, and the lower deck. The lower deck is typically mounted to an engine block adjacent one or more combustion chambers. The cylinder head is designed to control gaseous flow from the intake manifolds to the combustion chamber and from the combustion chamber to the exhaust manifolds. Generally, the gaseous flow passes through the lower deck. If required, the cylinder head may support a firing mechanism for each combustion chamber of the internal combustion engine. Because each of these requires openings to the combustion chamber through the lower deck, there are localized areas subject to increased levels of heat and stresses.
As a result of the operation of the internal combustion engine, the combustion chamber(s), cylinder head(s), piston(s), and other areas of the engine block are exposed to high levels of heat. This heat creates high thermal gradients from the heat of the combustion process, the cooling system, and other systems of the internal engine. These high thermal gradients create localized stress regions and potential hot spots within the lower deck of the cylinder head that can alter the alignment of the firing mechanism and other components in the internal combustion engine, thereby causing the internal combustion engine to operate inefficiently.
Generally, coolant flow paths may be provided in the cylinder head to draw heat from the hot spots. These flow paths assist in maintaining the cylinder head near a uniform temperature and reduces the likelihood of fracturing as the cylinder head temperature fluctuates. U.S. Pat. No. 4,690,104 (xe2x80x9cYasukawaxe2x80x9d) describes one such type of cylinder head. Yasukawa is directed to a cylinder head that provides plugs to speed up coolant flow in regions of large cross-sectional areas. In addition, Yasukawa provides several fins located on boss portions for securing the cylinder head to the engine block, as wells as on cylindrical walls that connect the intake and exhaust valves to the combustion chamber.
One drawback to Yasukawa is that neither the plugs nor the fins provide additional rigidity to the inner wall of the cylinder head. As a result, the inner wall experiences problems with stiffness and potential failure because of the cyclic loadings created by combustion of fuel in the combustion chambers.
The present invention solves one or more of the problems described above associated with known cylinder heads.
One aspect of the present invention is directed to a cooling chamber for a cylinder head. The cooling chamber may include a floor portion, a ceiling portion, and sidewall portions extending between the floor portion and ceiling portion. The cooling chamber may also include at least one exhaust port conduit extending through the cooling chamber from the floor portion towards the ceiling portion, at least one intake port conduit extending through the cooling chamber from the floor portion towards the ceiling portion, and a well portion. The at least one intake port conduit and the at least one exhaust port conduit may be disposed around the well portion. Finally, the cooling chamber may include a plurality of rib formations extending inwardly from the sidewall portions and a plurality of inlets arranged around a periphery of the cooling chamber. The rib formations are configured to deflect the coolant flow around the at least one intake port conduit and the at least one exhaust port conduit towards the well portion.
Another aspect of the present invention is directed at a method of cooling a cylinder head for an internal combustion engine. The cylinder head defining a cooling chamber having a floor portion, a ceiling portion, and sidewall portions extending between the floor portion and ceiling portion. The method includes introducing a coolant around a periphery of the cooling chamber through a plurality of inlets arranged at the periphery of the cooling chamber and directing the coolant flow from the inlets in the cooling chamber towards a well portion. The directing is regularly obstructing coolant flow at a predetermined location adjacent the side wall portions.